Bending machine with swinging-wing die carrier



BENDING MACHINE wm-x SWINGING-WING DIE CARRIER Filed April 2, 1954 L. B. GREEN 8 Sheets-Sheet 1 Aug. 5, 1958 IN V EN TOR.

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BENDING MACHINE WITH SWINGING-WING DIE CARRIER Filed April 2, 1954 8 Sheets-Sheet 3 37 ll a? 111 JM M fl I h i I n: Q *4 If 1 .4 u 2/ {L0 J7 I'l Q" I? Q 0 10a l 22 I i 's H 12:; i1 l r INVENTOR.

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55 8. Gaze @anll/ Arr-o Aug. 5, 1958 L. B. GREEN 2,845,935

BENDING MACHINE WITH SWINGING 'WING DIE CARRIER Filed April 2, 1954 8 Sheets-Sheet 5 I Arne/vi L. B. GREEN Aug. 5, 1958 BENDING MACHINE WITH SWINGING-WING DIE CARRIER Filed April 2, 1954 8 Sheets-Sheet 6 mmvroza. [5 8. GREEN L. B. GREEN Aug. 5, 1958 BENDING MACHINE WITH SWINGING-WING DIE CARRIER Filed April 2, 1954 8 Sheets-Sheet 7 INVENTOR. 45E 5.6REEN Aug. 5, 1958 B. GREEN BENDING MACHINE WITH SWINGING-WI Filed April 2. 1954 NG DIE CARRIER 8 Sheets-Sheet 8 United States Patent BENDING MACHINE WITH SWINGlNG-WING DIE CARRIER Lee B. Green, Lakewood, Ohio Application April 2, 1954, Serial No. 420,576

13 Claims. (Cl. 153-46) This invention relates to bending machines of the kind having cooperating relatively rockable wing and anvil die members for bending metal work pieces to curved shape, and as one of its objects, aims to provide an improved bending machine of the so-called tangent bender type which is relatively simple in its construction and operaof the character indicated in which the cooperating dies include an anvil die movable away from a clamping die by a reciprocable slide, and in which the anvil die is supported by the slide for swinging to a relatively offset and readily accessible work-receiving position simultaneously with, or during a portion of, such opening movement.

A further object is to provide such an improved bending machine in which the swinging of the anvil die to its relatively offset work-receiving position during the opening of the dies is accomplished by automatic means which is also eifective for returning the anvil die to a position substantially in alignment with the clamping die during the closing actuation of the anvil die by the slide.

Yet another object is to provide an improved bending machine of the kind above referred to in which retaining means associated with the anvil die retains the work thereon during movement of the anvil die from the loading position to its position of closed engagement with the clamping die.

It is likewise an object of this invention to provide a bending machine of this character in which the work-retaining means comprises yieldable holding members which are automatically retractable during closing of the anvil die and are also automatically returned to a work-receiving position during opening of the anvil die.

As another of its objects, this invention provides a bending machine of the tangent bender type having an upright frame structure with the cooperating dies located on the front side thereof, and in which the actuating means for the wing dies is located on the rear side of the frame structure and includes rearwardly extending rockshaft means.

Additionally, this invention provides an improved tangent bending machine of the kind indicated above in which the anvil die is swingable forwardly and away from the upright frame structure to a readily accessible work-receiving position during a downward opening movement of the anvil die by the slide, and in which the swinging of the anvil die is preferably accomplished 70 by cam means located on the rear side of the upright frame structure.

The invention can be further briefly summarized as consisting in certain novel combinations and arrangements of parts hereinafter described and particularly set out in the claims hereof.

In the accompanying sheets of drawings forming a part of this specification:

Fig. 1 is a front elevation of a bending machine embodying this invention;

Fig. 2 is a side elevation of the machine;

Fig. 3 is a rear elevation of the machine;

Fig. 4 is a partial front elevation corresponding with the upper portion of the machine of Fig. 1 and showing such portion on a larger scale;

Fig. 5 is a partial side elevation corresponding with the upper portion of the machine as illustrated in Fig. 2 and showing such portion on a larger scale;

Fig. 6 is a partial vertical section taken on section line 66 of Fig. 4;

Fig. 7 is a perspective view of the clamping die in detached relation;

Fig. 8 is a perspective view of one of the bending dies in detached relation;

Fig. 9 is a perspective view showing the clamping die support bracket in detached relation;

Fig. 10 is a perspective view showing one of the bending die carrier members in detached relation;

Fig. 11 is a partial vertical section taken through the anvil die and an adjacent bending die, substantially as indicated by section line 1111 of Fig. 5, and showing the bending die ready to begin its bending stroke; and

Fig. 12 is a partial vertical section similar to Fig. 11 but showing the position of the bending die at the completion of the bending stroke.

The improved bending machine 10 is operable on work pieces, in this instance two work pieces simultaneously such as the metal members 11, for bending such work pieces to a curved shape. The machine is particularly suitable for carrying out such bending operations on work pieces of a flanged cross-sectional shape and rapidly and economically accomplishes such :bending operations by bending one of the flanges, such as the flange 11a of the work piece 11, out of its own plane and simultaneously bending the other flange 11b within its own plane. The bending of the flange 1111 within its own plane is accomplished smoothly and without buckling or wrinkling and without need for previous notching of the material.

The bending machine 10 comprises in general a frame structure 12, which in this instance is an upright frame structure, and a plurality of cooperating dies supported on the front side of such frame structure and operable to perform the above-mentioned bending operation on the work pieces 11. The cooperating dies comprise an upper die group 13 and a lower anvil die 14 movable relative thereto. The die group 13 comprises a clamping die 15 with which the anvil die 14 cooperates in clamping the work pieces 11 therebetween, and a pair of bending dies 16 and 17 located on opposite sides of the clamping die and adapted for bending cooperation with the anvil die.

The frame structure 12 comprises a supporting base 18 on which the machine is adapted to rest or stand, and an upright plate portion or member 19 having its lower end suitably secured to the base as by connecting means which includes the bracket members 20. At a point adjacent the upper end of the frame structure 12, thev plate portion 19 is provided with a laterally elongated opening 21 extending therethrough, and at a point spaced below the opening 21 is provided with a second opening 22. The purpose of the openings 21 and 22 will appear hereinafter.

The anvil die 14 is generally a flat plate member having a work-engaging upper end which is made of a shape to suit the shape to which the work pieces 11 are to be bent. Such work-engaging upper end is provided with convexly rounded side portions 24 and a laterally straight intermediate clamping portion 25 extending between and merging with the rounded side portions. The rounded side portions 24 are of a shape or radius of curvature corresponding with the curved shape to which the work pieces 11 are to be bent. The body portion 14a of the anvil die is relatively thicker than its edge portions which include the clamping portion 25 and the rounded side portions 24.

The clamping die 15 comprises a laterally elongated metal block having a channel-shaped longitudinal die groove 26 in the underside thereof and is carried by a forwardly projecting portion 27 of a mounting bracket 28. The bracket 28 is secured to the plate member 19 in fixed relation thereto by means of screws 29. The clamping die 15 is held against the underside of the forwardly projecting bracket portion 27 by means of a clamping screw 31 extending through an opening 27:: of such projecting por tion and engaged in a threaded opening 30aof the clamping die. As shown in Figs. 4, 7 and 12, the clamping die 15 also has laterally projecting end lugs 15a thereon which lie in the same plane as the groove 26 and whose purpose will be explained hereinafter. The lugs 15a are provided at the top thereof with a bevel surface 15b which slopes laterally and downwardly at an angle of approximately 45.

The clamping die 15 is adjustably movable vertically of the plate member 19 by vertical shifting of the bracket 28 which, in this instance, is produced by an adjusting screw 31 threadedly mounted in a forwardly overhanging frame projection 32. To permit such adjusting movement of the bracket 28, the openings 33 thereof through which the clamping screws 29 extend are of an enlarged or slot-like shape, as indicated in Figs. 4 and 5.

The bending dies 16 and 17 are here shown as being laterally elongated metal block members having their inner or adjacent ends in substantially abutting engagement with the clamping die 15, and are provided in the underside thereof with laterally extending die grooves 34 of substantially the same channel-like cross-sectional shape and lying substantially in the same vertical plane as the die groove 26 of the clamping die. The bending dies 16 and 17 are mounted respectively in wing-type carriers 35 and 36 for rocking movement around the curved side portions 24 of the anvil die 14.

The inner ends of the bending dies 16 and 17 are maintained in aligned relation with the clamping die 15 by the engagement of the end lugs 15:: of the latter in the grooves 34 of the bending dies. For this purpose, the grooves 34 are provided at the inner end thereof with enlargement or recess portions 34a which receive the end lugs 15a and are defined in part by laterally and downwardly sloping faces 34b adapted to rest on the sloping surfaces 15b of the end lugs.

As shown in Figs. 4, 5, 6 and 10, the carrier 35 and 36 comprise wing members 35a and 36a supported by rock shafts 35b and 3619 with which the wing members are integrally connected. The wing members 35a and 36a are of an inverted-L shape and each comprises a flat vertical arm 37 extending upwardly from the r-ockshaft and a second fiat arm 38 carried by the vertical arm and projecting therefrom in a forwardly overhanging relation to the anvil die 14. The carriers 35 and 36 also comprise front and end plates 39 and 40 which are secured by clamping screws 39a and 40a to the arms 37 and 38 and cooperate with the latter in defining pockets 41 for the bending dies 16 and 17.

The bending dies 16 and 17 are mounted on their carriers 35 and 36 by being located in the pockets 41 and have their inner ends projecting from such pockets and engaging the clamping die 15. 'Pressure plates 42 are also disposed in the pockets 41 and are located between the bending dies and the arms 38 of the wing members 35a and 360. These pressure plates 42 preferably have antifriction material 42a on the underside thereof for hearing engagement with the tops of the bending dies. The bending dies are adjustable downwardly in the pockets 41 by movement imparted to the pressure plates 42 by adjusting screws 42b extending through threaded openings of the arms 38 of the wing members 35a and 36a. The bending dies 16 and 17 have limited endwise movement in the pockets 41 and are shiftable toward the clamping die 15 by adjusting screws 43 which extend through threaded openings of the end plates 39 and 40 and carry lock nuts 43a.

The rockshafts 35b and 36b extend rearwardly through the upper opening 21 of the plate member 19 and provide a means by which these carrier are supported and actuated. The rockshafts 35b and 3615 are journalled in bearing blocks 46 and 47 located on the rear side of the plate member 19. The bearing blocks 46 and 47 are disposed in a pair of laterally aligned guideways 48 and 49 defined by pairs of upper and lower guide members 50 and 51 which are secured against the rear side of the plate member 19 by suitable clamping screws 52.

The guideways 48 and 49 provide for adjustment of the lateral spacing of the rockshafts 35b and 36b and of the bending dies 16 and 17 for cooperation with clamping and anvil dies of different dimensions and thus adapting the machine for operation on workpieces of various lengths. The bearing blocks 46 and 47 are maintained at the desired spacing and against outward spreading relative to each other by means of suitable adjusting and clamping screws 54 extending through adjusting brackets 55 mounted on the rear side of the plate member 19.

The anvil die 14 is mounted on a swingable anvil die carrier 56 which, in turn, is supported by a reciprocably movable slide 57. The slide 57 is movable in a vertically extending guideway 58 which is defined by a pair of guide members 59 and 60 mounted on the front side of the plate member 19 and by a pair of cover plates 61 and 62 attached to such guide members. The guide members 59 and 60 are secured against the front side of the plate member 19 as by means of the clamping screws 63 and the cover plates 61 and 62 are secured to such guide members by the clamping screws 64.

The guideway 58 guides the reciprocating movements of the slide 57 such that the anvil die 14 is movable upwardly and downwardly toward and away from the die group 13. When the anvil die 14 is moved to its upper or closed position, the intermediate portion 25 of the upper end of this die is engaged in the groove 26 of the clamping die 15 and the rounded side portions 24 are engaged in the adjacent ends of the grooves 34 of the bending dies 16 and 17. In this closed position of the anvil die 14 the intermediate portions of the work pieces 11 are clamped between the die portion 25 and the clamping die 15 while the end portions of the work pieces extend laterally outwardly in overhanging relation to the curved side portions 24 in readiness to be bent around the latter by the bending dies.

Fig. 11 further illustrates the clamped condition of the work 11 between the anvil die 14 and the clamping die 15, and also shows the bending die 17 ready to begin its rocking movement around the curved anvil die portion 24 for bending the work around the latter. Fig. 12 shows the bent condition of the Work 11 after the completion of the bending stroke through which the die 17 is moved by its carrier 36. During such actuation of the bending die 17, relative sliding takes place between this die and the bearing surfacing material 42a of the pressure plate 42. The extent of this relative sliding movement can be seen from Fig. 12. The bending die 16 is, of course, actuated in this same manner by its carrier 35.

The anvil die carrier 56 is a plate member which is provided at its lower end with an end thrust face 65 and a pair of forwardly projecting hinge lugs 66 adjacent such thrust face. The carrier 56 also comprises a transverse shoulder 67 and a rear plate portion 56a of reduced thickness which extends upwardly beyond the shoulder 67. In the rear face thereof, the carrier 56 is provided with a vertical slot or keyway 68.

The slide 57 comprises a plate member 57a having its edge portions slidable in the guideway 58. A hinge bracket 69 is mounted on the front of the plate member 57a adjacent its lower end and is secured thereto by clamping screws 70 and a laterally extending key 71. The bracket 69 has a thrust face 72 thereon against which the end "thrust face 65 of the carrier 56 is adapted to seat, and a pair of hinge lugs 73 which extend forwardly in cooperating relation to the hinge lugs 66 of the anvil die carrier 56. The plate member 57a is provided on the front side thereof with a key 74 which is secured thereto by screws 74a and which extends vertically along this plate member above the thrust face 72 and is substantially aligned with the keyway 68 of the carrier 56 for engagement in the latter. The plate member 57a also has an opening 75 therein lying in front of the opening 22 of the plate member 19.

The anvil die carrier 56 is swingably connected with the slide 57 by a hinge pin 76 which connects the pairs of hinge lugs 66 and 73. The carrier 56 thus supports the anvil die 14 for swinging movement toward and away from the plate member 19 of the frame structure 12 such that the anvil die can be swung toward the plate member to assume a position in the plane of, or in register with, the grooves of the clamping and bending dies. The carrier 56 also provides for swinging of the anvil die 14 in a direction away from the plate member 19 to a workreceiving or loading position in which the anvil die extends in an outwardly and upwardly inclined relation in front of the plate member, as represented by the broken line anvil die position 14b shown in Figs. 2 and 5.

It is desirable to have the thrust of the bending operation transmitted directly to the anvil die carrier 56 and the slide 57 rather than have such thrust transmitted through clamping screws or through the hinge pin 76. The anvil die 14 is therefore mounted on the carrier 56 with its lower end seating against the transverse shoulder 67. The anvil die is secured to the carrier 56 in this position by clamping screws '77 extending through the body portion 14:: of the anvil die. When the carrier 56 has swung the anvil die 14 into alignment with the grooves of the clamping and bending dies, the keyway 68 of the carrier will be engaged with the key 74 of the slide 57 and the thrust face 65 of the carrier will be seated against the thrust face 72. of the slide. The engagement of the keyway 68 with the key 74 will prevent lateral shifting of the carrier relative to the slide, and the engaged faces 65 and 72 will transmit the downward thrust of the bending operation to the slide directly rather than through the hinge pin 76.

The swinging movements of the anvil die carrier 56 on the slide 57 and relative to the plate member 19 are produced by suitable actuating means, preferably a cam means shown in this instance and comprising a guideway or cam track 78 and a cam follower 79. The cam track 78 is provided on the rear side of the plate member 19 and is defined by substantially parallel inclined faces 80 and 81 of a pair of bracket members 82 and 83 suitably secured to such plate member. The cam track 78 is accessible from the front side of the plate member 19 through the opening 22 of the latter.

The cam follower 79 is here shown as being in the form of a roller rotatably mounted on a pivot pin 84 which is carried by an arm 85 projecting rearwardly from the anvil die carrier 56 and extending into or through the opening 22 of the plate member 19. The location of the cam track 78 and its direction of inclination are such that, upon downward movement of the slide 57 from a 6 position corresponding with the closed condition of the anvil die 14 shown in Figs. 5 and 6, the cam follower 79 will engage in the cam track and during downward movement in the latter will cause the carrier 56 to be swung in a forward direction away from the plate member 19.

As the slide 57 continues its downward travel for producing a further opening movement of the anvil die 14, the cooperation of the cam follower 79 with the cam track 78 will swing the anvil die to its forwardly inclined loading position 14b by the time that the slide has reached the lower end of its downward opening movement. During the subsequent upward movement of the slide 57 for causing closing of the anvil die 14 relative to the clamping die 15 and the bending dies 16 and 17, the cam follower 79 will move upwardly and inwardly along the cam track 78, thereby swinging the anvil die inwardly from its loading position 14b to a position in which its upper end is substantially aligned with the groove 26 of the clamping die 15.

This inward swinging movement of the anvil die 14 by the cam means will be completed as the upper end of the anvil die approaches the clamping die 15 such that the final portion of the upward movement of the slide 57 will cause the upper end of the anvil die to enter the slot 26 of the clamping die and the slots of the bending dies 16 and 17, thereby carrying the work pieces 11 into such slots and clamping them against the clamping die. When the anvil die has thus been moved to its closed position, as illustrated in Figs. 5 and 6, the machine is ready for the bending operation to be carried out by the rocking of the bending dies 16 and 17 around the curved side portions 24 of the anvil die.

The above-described opening and closing movements of the slide 57 are produced by suitable power means, in this instance by a power cylinder device 86 located on the front side of the plate member 19. The power cylinder device 86 comprises a double-acting fluid pressure cylinder 87, and a piston rod 88 projecting from such cylinder and having its upper end connected with the slide 57 by means of the yoke 89 and yoke pin 90. The lower end of the cylinder 87 is anchored on the frame structure 12 as by means of a bracket 91 of the latter and a yoke 92 carried by the cylinder and secured to the bracket by the yoke pin 93.

For actuation of the bending dies 16 and 17 through the rockshafts 35b and 36b, a suitable power device is provided on the rear side of the plate member 19 such as the power cylinder device 94. The power cylinder device 94 comprises a double-acting fluid pressure cylinder 95, and a piston rod 96' projecting from the lower end of such cylinder and connected with a crosshead 97. The upper end of the cylinder is anchored on the frame structure 12 as by means of the bracket 98 projecting from the plate member 19 and a yoke portion 99 of the cylinder which is connected with such bracket by the yoke pin 100.

The crosshead 97 is reciprocably movable in a guideway 101defined by a pair of guide members 102 mounted on the plate member 19 at the rear side thereof. The crosshead 97 has a pair of laterally extending arms 103 and 104 which are connected with crank arms 10S and 106 of the rockshafts 35b and 36b by means of push-pull links 107 and 108.

Swinging movement of the bending dies 16 and 17 to their open or upper position shown in Figs. 1 and 4 is produced by an upward return movement of the piston rod 96 and is limited in extent by adjustable stop screws 109 provided on the wing members of the carriers 35 and 36. The downward closing movement or bending stroke of the dies 16 and 17 is produced by a downward movement of the piston rod 96 and the crosshead 97, by which a downward pull is transmitted through the links 107 and 108 to the crank arms 110 and 111 of the rockshafts 35b and 36b. This downward movement of the l crosshead 97 is limited in extent by an adjustable stop screw 112 provided on this crosshead.

When the anvil die 14 has been swung to its loading position 145, the work pieces 1 can be conveniently placed on the work-receiving upper end of this die in the relative position shown in Figs. 5 and 6 preparatory to such anvil die being swung inwardly and advanced into closed relation with the clamping die 15. For retaining the work pieces 11 on such upper end of the anvil die 14, substantially T-shaped work-retaining members 113 and 114 are provided on opposite sides of the anvil die and which engage the work pieces and temporarily press or hold the same against the anvil die for retaining them thereon.

The work-retaining members 113 and 114 are here shown as comprising laterally elongated grip bars having rounded head or top edge portions 113a and 114a, and resilient blade spring support arms 115 and 116 on the upper ends of which the grip bars are riveted or otherwise secured. The resilient support arms 115 and 116, together with the transversely extending grip bars carried thereby, constitute the T-shaped work-retaining members 113 and 114. The arms 115 and 116 are connected with and carried by plungers 117 and 118 which are slidable in vertically extending guideways 119 and 120. These guideways are located on opposite sides of the body portion 14a of the anvil die 14 and are formed by channel shaped members 121 and 122 secured thereagainst by the screws 123 and 124. V

The plnngers 117 and 113 are urged upwardly in the guideways 119 and 121) by compression springs 125 and 126 to move the grip bars 113 and 114 upwardly alongside the anvil die 14 to an extended position illustrated in the broken line showing in Fig. 5, in which position they are ready to receive the Work pieces 11.. When the grip bars are in this extended position, they can be readily spread away from the anvil die 14 by flexing of the resilient arms 115 and 115 for the insertion of the work pieces 11. When the work pieces have been thus inserted, the resilient arms 115 and 116 urge the grip bars toward the anvil die and press the work pieces thereagainst for retaining them on the upper end of such anvil die.

During the closing movement of the anvil die 14, as above described, during which its upper end carries the work pieces 11 into the groove 26 of the clamping die 15, the rounded portions 113a and 114a of the grip bars come into engagement with the clamping die and are thereby moved downwardly out of engagement with the work pieces 11 and to their retracted position shown in Fig. 6. During the downward opening movement of the anvil die 14 and the retraction of this die from the groove 26 of the clamping die following the completion of the bending operation, the springs 125 and 126 actuate the plungers 117 and 118 to thereby extend the grip bars 113 and 114 to their work-receiving position adjacent the upper end of the anvil die. During this upward extending movement of the grip bars 113 and 114, they will act as a stripper means and will engage and dislodge the formed work pieces from the anvil die and thus facilitate their removal from the machine. By the time that the anvil die has been swung to its loading position 14b following a bending operation, the formed work pieces will be removed by the operator and the anvil die will be ready to receive the work pieces for the next bending operation.

From the accompanying drawings and the foregoing detailed description, it will now be readily understood that this invention provides a bending machine of the tangent bender type which is of a relatively simple and compact construction, and by which bending operatlons can be rapidly and smoothly carried out on successive work pieces. It will now also be seen that this improved bending machine has an upright position with the cooperating dies on the front side of the frame structure- '8 and with the anvil die swingable forwardly to a loading position in which its work-receiving portion is readily accessible for quickly and easily applying the work thereto. Additionally, it will be seen that this bending machine includes means for causing such swinging movement of the anvil die between its loading position and a position in alignment with the clamping and bending dies, and also embodies novel work-retaining means for retaining the work on the anvil die preparatory to the engagement of the latter with the clamping and bending dies for the bending operation.

Although this novel bending machine has been illustrated and described herein to a somewhat detailed extent, it will be understood, of course, that the invention is not to be regarded as being limited correspondingly in scope, but includes all changes and modifications coming within the terms of the claims hereof.

Having thus described my invention, I claim:

1. In a bending machine, a frame, a pair of cooperating dies comprising an anvil die adapted to receive a workpiece thereon and a bending die rockably movable relative to said anvil die when the latter is in a die-closed position for bending the workpiece around said anvil die a first carrier means supporting said anvil die with the anvil die projecting from one end of said first carrier means, a second carrier means supporting said bending die and providing for the rocking of said bending die relative to said anvil die, hinge means substantially at the other end of said first carrier means and supporting the latter for swinging relative to said frame for moving said anvil die to a relatively offset work-receiving position and from such work-receiving position to a second position substantially in alignment with said bending die, means for actuating said first carrier means for moving said anvil die to and from said die-closed position, and cam means for directly and swingably actuating said first carrier means for causing the movement of said anvil die to said work-receiving and second positions, said cam means comprising reactively cooperating cam track and cam follower elements one of which is attached to said frame and the other of which is attached to said first carrier means at a point spaced from said hinge means.

2. In a bending machine, a frame, a pair of cooperating dies comprising an anvil die adapted to receive a workpiece thereon and a bending die rockably movable relative to said anvil die for bending the workpiece around the latter, carrier means supporting said anvil die, carrier means supporting said bending die and providing for the rocking of said bending die relative to said anvil die, the carrier means for said anvil die having an opening and closing reciprocable movement relative to said bending die and also having a substantially simultaneous swinging movement in a direction substantially transverse to the plane of said reciprocable movement for moving said anvil die between a relatively offset workreceiving position defining an acute angle with said plane and a second position substantially in said plane and in alignment with said bending die, and cam means responsive to said reciprocable movement for swinging the carrier means during the reciprocable opening and closing movements of the latter.

3. In a bending machine, a frame structure, a pair of cooperating dies adapted to receive a workpiece therebetween and comprising an anvil die having a curved portion on one end thereof and a bending die rockable relative to said anvil die for bending the workpiece around said cured portion, mounting means mounting said bending die on said frame and providing for the relative rocking movement thereof, means on said frame defining a guideway, a slide supporting said anvil die with said one end of the latter extending toward said bending die, said slide being movable along said guideway for causing opening and closing movements of said anvil die relative to said bending die, hinge means connecting the other end of said anvil die with said slide for swinging of the anvil die relative to the latter and in a direction substantially transverse to the plane of said guideway, and cam means operable to swing the anvil die during at least a portion of the movement of said slide along said guideway.

4. A bending machine as defined in claim 3 in which said cam means comprises a cam track on said frame structure and a cam follower connected with said anvil die and cooperating with said cam track during at least a portion of the travel of said slide along said guideway.

5. In a bending machine, a frame structure, a pair of cooperating dies adapted to receive a workpiece therebetween and comprising an anvil die having a curved portion and a bending die rockable relative to said anvil die for bending the workpiece around said curved portion, mounting means mounting said bending die on said frame and providing for the relative rocking movement thereof, a carrier having said anvil die mounted thereon with said curved portion projecting from one end of said carrier and extending toward said bending die, a slide supporting said carrier and being movable along said guideway for causing closing and opening movements of said anvil die relative to said bending die, hinge means swingably connecting the other end of said carrier with said slide for swinging of said anvil die in a direction extending substantially transverse to the plane of said guideway between a first work-receiving position relatively offset from said bending die and a second position substantially in alignment with said bending die, and cooperating cam elements connected respectively with said frame structure and carrier and effective on said carrier for swinging said anvil die between said first and second positions during movement of said slide along said guideway.

6. In a bending machine, a frame structure having an upright plate portion, a group of cooperating dies comprising an upright anvil die having curved side por tions on the upper end thereof and a pair of bending dies rockable relative to said anvil die for bending portions of a workpiece around said curved side portions, means mounting said bending dies on said plate portion and providing for the rocking of said bending dies relative to said anvil die, a substantially vertical guideway on said plate portion, a slide reciprocably movable in said guideway, a carrier having said anvil die mounted thereon, and means connecting the lower end of said carrier with said slide for opening and closing movements of said anvil die relative to said bending dies including a substantially horizontal-axis hinge means providing for swinging of said anvil die in a direction extending substantially transverse to the plane of said guideway and away from said plate portion to a work-receiving position.

7. In a bending machine, a frame structure having an upright plate portion, a group of cooperating dies comprising an anvil die having curved side portions and a pair of bending dies rockable relative to said anvil die for bending portions of a workpiece around said curved side portions, means mounting said bending dies on said plate portion and providing for the rocking of said bending dies relative to said anvil die, a substantially vertical guideway on said plate portion, a slide reciprocably movable in said guideway, a carrier having said anw'l die mounted thereon, means connecting said carrier with said slide for opening and closing movements of said anvil die relative to said bending dies including pivot means providing for movement of said anvil die to a work-receiving position by swinging of said carrier away from said plate portion, said plate portion having an opening therein, cam means on said frame structure and accessible through said opening, and an arm connected with said carrier and having follower means engageable with said cam means through said opening.

8. In a bending machine of the kind having a rockably movable bending die, a fixed clamping die and an anvil die having a work-engaging portion including a curved '10 side portion relative to which said bending die is rockable for bending work therearound; a carrier having said anvil die mounted thereon and being movable toward and away from said clamping die for causing opening and closing movements of the anvil die relative to the latter; work retaining means comprising resilient arm means having a. holding portion for clamping cooperation with said workengaging portion of said anvil die for retaining work on the latter during closing movement of the anvil die relative to said clamping die; the yieldable character of said arm means being effective to urge said holding portion into work-clamping cooperation with said work-engaging portion of the anvil die; and means mounting said retaining means on said carrier for retracting movement relative to the carrier for shifting said holdingportion away from said work-engaging portion to automatically release the work, during the final portion of the closing movement of said anvil die relative to said clamping die; portions of said retaining means being engageable with said clamping die during said final portion closing movement for causing said retracting movement of the retaining means.

9. In a bending machine of the kind having a pair of rockably movable bending dies, a fixed clamping die therebetween and an anvil die having a work-engaging portion including curved side portions relative to which said bending dies are rockable for bending work therearound; a carrier having said anvil die mounted thereon and being movable toward and away from said clamping die for causing opening and closing movements of vthe anvil die relative to the latter; work retaining means having a holding position in which a holding portion of said retaining means lies adjacent to and has clamping cooperation with said work-engaging portion of said anvil die for retaining work on the latter during closing movement of said anvil die relative to said clamping die; and means mounting said retaining means on said carrier for retracting movement relative to the carrier for shifting said holding portion away from said work-engaging portion to automatically release the work, during the final portion of the closing movement of said anvil die relative to said clamping die; portions of said retaining means being engagea'ble with said clamping die during said final portion closing movement for causing said retracting movement of the retaining means.

10. In a bending machine of the kind having a pair of rockably movable bending dies, a fixed clamping die therebetween and an anvil die having a work-engaging portion including curved side portions relative to which said bending dies are rockable for bending work therearound; a carrier having said anvil die mounted thereon and being movable toward and away from said clamping die for causing opening and closing movements of the anvil die relative to the latter; work retaining means cooperating with said work-engaging portion of said anvil die for retaining work on the latter during closing movement thereof relative to said clamping die; means mounting said retaining means on said carrier for movement with the latter; said mounting means also providing for extending and retracting movements of said retaining means relative to said carrier for movement of said retaining means into and out of a position of holding cooperation'with said work-engaging portion; and spring means effective on said retaining means and normally tending to produce said extending relative movement of said retaining means to said position of work-holding cooperation with said work-engaging portion; said retaining means being engageable with, and movable through said retracting move ment by, said clamping die in opposition to said spring means during the final portion of the closing movement of said anvil die relative to said clamping die.

11. Bending machine construction as defined in claim 10 in which the extending and retracting relative movement of said retaining means is alongside of and substantially parallel with said anvil die.

12. Bending machine construction as defined in claim '11 10 in which said retaining means comprises retaining members located on opposite sides of said anvil die; and in which the extending the retracting relative movement of said retaining means comprises movement of said retaining members alongside of'and substantially parallel with said anvil die.

13. Bending machine construction as defined in claim 10 in which said retaining means comprises a substantially T-shaped member; and in which the transversely extending top portion of the T-member has a rounded crosssectional shape and is adapted for said work-holding cooperation with said work-engaging portion of the anvil die and for engagement with said clamping die during said final closing movement.

14. Bending machine construction as defined in claim 10 and which includes a substantially vertically movable slide and pivot means connecting said carrier with said slide for swinging of said anvil die from an inner position substantially in alignment with said clamping die to an outwardly inclined work inserting position.

l5. Bending machine construction as defined in claim 10 and which includes a substantially vertically movable slide and pivot means connecting said carrier with said slide for swinging of said anvil die from an inner position substantially in alignment with said clamping die to an outwardly inclined work inserting position; and which construction also includes cam means for producing such swinging of said anvil die.

16. In a bending machine, a frame structure having an upright plate portion provided with an opening, means defining a transversely extending guideway on the rear side of said frame structure and adjacent said opening, a group of dies having grooved work-engaging portions comprising a pair of bending dies and a clamping die disposed between said bending dies and secured to said frame structure, an anvil die having at substantially the upper end thereof a work-engaging portion comprising a clamping portion for cooperating with said clamping die and curved side portions on opposite sides of said clamp ing portion, bearing members mounted in said transversely extending guideway, wing members supporting said bending dies and having rock shafts journaled in said bearing members and extending through said opening, power cylinder means on the rear side of said plate portion and connected with said rock shafts for actuating said bending dies in rocking cooperation with said curved side portions of said anvil die, said bearing members being adjustable along said transversely extending guideway for varying the spacing of said bending dies, means for maintaining said bearing members in their adjusted positions, means located on the front side of said plate portion defining a substantially vertical guideway below said group of dies, a slide supporting said anvil die and being movable in said vertical guideway for causing opening and closing movements of said anvil die relative to said clamping die, and power cylinder means on the front side of said plate portion and connected with said slide to actuate the same.

17. In a bending machine having an upright frame structure supporting a pair of dies having grooved workengaging portions and comprising a rockably movable bending die and a fixed clamping die; an anvil die having at the upper end thereof a work-receiving portion comprising a clamping portion for cooperation with said clamping die and a curved side portion relative to which said bending die is rockable for bending the work therearound; means on said frame structure defining a substantially vertical guideway below said pair of dies; a slide operable in said guideway; a carrier having said anvil die mounted thereon; pivot means connecting said carrier with said slide for swinging of said upper end of said anvil die away from said frame structure to a work inserting position and for swinging of said upper end of said anvil die with the work thereon toward said frame structure and to a position substantially in a vertical plane which includes the grooved portions of said clamping and bending dies; yieldable work-retaining means having a holding portion cooperating with said work-receiving portion for retaining the work on said upper end of said anvil die; the yieldable character of said work-retaining means being effective to urge said holding portion into work-clamping cooperation with the work-receiving portion of the anvil die; and means mounting said retaining means on said carrier for retracting movement relative to the carrier for shifting said holding portion away from said work-receiving portion to automatically release the work, during the final portion of the closing movement of said anvil die relative to said clamping die; portions of said retaining means being engageable with said clamping die during said final portion closing movement for causing said retracting movement of the retaining means,

18. In a bending machine having an upright frame structure supporting a pair of dies having grooved workengaging portions comprising a rockably movable bend ing die and a fixed clamping die; an anvil die having at the upper end thereof a work-receiving portion comprising a clamping portion for cooperation with said clamping die and a curved side portion relative to which said bending die is rockable for bending the work therearound; means on said frame structure defining a substantially vertical guideway below said pair of dies; a slide operable in said guideway; a carrier having said anvil die mounted thereon; pivot means connecting said carrier with said slide for swinging of said upper end of said anvil die away from said frame structure to a work inserting position and for swinging of said upper end of said anvil die with the work thereon toward said frame structure and to a position substantially in a vertical plane which includes the grooved portions of said clamping and bending dies; cooperating carn members connected respectively with said carrier and said frame structure and effective to cause said swinging of said anvil die relative to said frame structure; yieldable work retaining means having a holding portion cooperating with said work-receiving portion for retaining the work on said upper end of said anvil die; the yieldable character of said work-retaining means being eifective to urge said holding portion into workclamping cooperation with the work-receiving portion of said anvil die; and means mounting said retaining means on said carrier for retracting movement relative to the carrier for shifting said holding portion away from said work-engaging portion to automatically release the work, during the final portion of the closing movement of said anvil die relative to said clamping die; portions of said retaining means being engageable with said clamping die.

during said final portion closing movement for causing said retracting movement of the retaining means.

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